You don’t imagine a 4,000-page doorstop of a government report making a splash, but this one is: The Bureau of Land Management’s June draft report on the possible environmental effects of the Southern Nevada Water Authority’s proposed pipeline plan. In case you’ve been living under a mesquite tree: As drought insurance, the authority wants to build a more than 300-mile network of pipes into central-eastern Nevada to send water to the Las Vegas Valley. For the water, it needs a nod from the state engineer. But for rights of way, it needs approval from the BLM — which, among many enviros and conservationists, is often seen as, well, a bunch of pushovers.

Which is why opponents of the pipeline plan are pleasantly surprised at the report’s sometimes strong language. In a nutshell, the BLM concludes that the pipeline, which aims to withdraw as much as 176,000 acre-feet of groundwater a year, could drop water tables, dry up sensitive land, kill off native vegetation and hurt federally protected animals.

“It’s a pretty damning report,” says Rob Mrowka of the Center for Biological Diversity. “I’m pleasantly surprised by what the BLM put into the report.” Mrowka encapsulates the report like this: “If you thought your future generations of grandkids and great grandkids were going to enjoy the same Nevada you enjoy as far as hunting, fishing, hiking and rural community, you’re wrong, because the landscape will be dramatically changed for the worse if this pipeline goes through.”

Zane Marshall, director of the environmental resources department at the authority, says this report is hardly the last word. He’s got a few technical objections, and notes that the BLM’s scenarios about environmental impacts over the next 200 years are just that — scenarios — that don’t account for unknowns such as where the authority will actually sink its wells.

“This is a long-term project and long-term process,” says Marshall, who will respond to the report as part of the comment period. “We’re not planning this for tomorrow. This is a project for decades.” Read the report and learn how to comment on it at www.blm.gov/5w5c.